Diffuse & transparency image import
These settings are render engine dependent, that means the options available depend on which rendering engine you are currently using, like Cycles or Blender Internal (Also called Blender Render).

On the info window you can change the render engine:



Transparency and emission options are material properties and the addon must be able to create a material with those properties for rendering system currently in use, so some options are only available for Blender Internal materials others for Cycles, since they use completely different and independent material definitions.

To see the options for each render engine read this post:

Long story short, decide which render engine you are going to use, then if the desired options aren't immediately available from the importer adjust you material manually afterwards.